-  II,  5 


y    * 


I  .  S.  DEPAR  I'Ml'N  1    OF   AGRICULTURE 

BUREAU   OF   ENTOMOLOGY     CIRCULAR   No.   163. 

L.  O.   HOWARD.   F-ntomologiM  and  (  h.rf  „MW.u. 


HYDROCYANIC-ACID  (i.\S  A(JAINST 
HOUSEHOLD  INSECTS. 


BY 


L.  O.   HOWARD  and  C.   II    POPENOE. 


war -it 


WMHINQTON  :  OOVEHNMEMT  POIMTtNtt  OFFICE  !  1(12 


BUREAU  OF  ENTOMOLOGY. 

L.  O.  Howard,  Entomologist  and  Chief  of  Bureau. 

O.  L.  Marlatt,  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 

R.  S.  Clifton,  Executive  Assistant. 

W.  F.  Tastet,  Chief  Clerk. 

F.  H.  Ghittendew',  in  charge  of  truck  crop  and  ston  d  product  insect  investigations. 
A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 
W.  1).  Hunter,  in  charge  of  southern  field  crop  insect  investigations. 
F.  M.  YVkisster,  in  charge  of  cereal  and  forage  insect  investigations. 
A.  L.  Quaintance,  in  charge  of  deciduous  fruit  insect  investigations. 
E.  F.  Phillips,  in  charge  of  bee  culture. 

D.  M.  Rogers,  in  charge  of  preventing  spread  of  mollis,  /,>/,/  work. 
ROLLA  P.  CURRIE,  Ml   charge  of  libra))/. 
X 


ADDITIONAL  COPIES  of  this  publication 
Xjl  may  he  procured  from  the  Superintend- 
ent of  Documents,  Government  Printing 
Office,  Washington,  D.  C  ,  at  5  cents  per  copy 


Circular  No.  163.  imutA  NoTemtx 

Doited  States  Department  of  Agriculture, 

BUREAU   OF   ENTOMOLOGY. 
L     O     HOWARD,    Entomologist    and    Chief   of    Bureau. 


HYDROCYANIC-ACID   GAS   AGAINST   HOUSEHOLD   INSECTS. 
Bj   I..  « >.  How  led  and  '>'.  ll.  Popi  si 

Hydrocyanic-acid  gas  ia  one  of  the  most  effecl  ive  remedies  known 
against  various  classes  of  insects.  For  more  than  20  years  it 
baa  been  the  principal  means  of  controlling  scale  insects  <>n  citrus 
in  California  and  is  do^k  in  general  use  for  the  disinfection  of 
all  deciduous  nursery  stock  and  other  plant  material  l'<u-  shipment, 
ami  is  one  of  the  m< »-t  effective  methods  of  i-i <  1» I i 1 1  ir  greenhouses  and 
cold  frames  of  plant-lice,  thrips,  white  flies,  and  various  scale  pots 
which  infesl  plants  grown  under  glass.1  It  has  also  become  a  stand- 
ard remedy  against  the  M<  diterranean  flour  moth  and  other  mill  and 
grain  insed 

It  has  been  fully  demonstrated  that  this  gas,  which  i<  very  deadly 
to  all  forms  of  animal  life.  i-.  under  proper  precautions,  an  excellent 
remedy  for  household  ii  sects.  Probably  it-  lit-'  use  for  this  purpose 
a  June  of  1898,  by  Mr.  C.  L.  Marlatt,  of  this  bureau,  against  book 
lice  in  the  residence  of  an  employee  of  the  I  department  <>(  Agriculture, 
using  the  cyanid  first  at  the  ordinary  strength  employed  on  fruit 
n  double,  and  finally  quadruple  the  strength.  The  book  lice 
came  from  recently  introduced  leather-covered  furniture,  the  cover- 
ing of  which  was  so  tightly  fastened  a-  to  In-  almost,  if  not  quite. 
impervious  to  the  gas,  and  the  treatment  was  only  partially  succes- 
ful.  Another  early  use  of  this  ira-  for  household  insects  was  in  1899 
iii  San  Francisco  by  the  late  Alexander  Craw,  then  Chief  Qua  rani  me 
Officer  of  the  Board  of  I  lorticulture.  In  this  case  it  was  used  against 
bedbugs  ami  in  very  -mall  proportions.  Two  and  one-half  fluid 
ounces  of  commercial  sulphuric  acid  and  -j\  ounce-  98  percent  cyanid 
of  potassium  were  used  in  a  house  of  several  rooms,  each  containing 
•boat  2,250  cubic  feet  of  -pace.  The  rooms  were  closed  for  two 
hour-,   then    well    aired.      The   operation    .\a-   apparently    successful. 

IF    rrn.-r-'    Bui' 
letln    ITS. 

•  Refer  to  Clrcnlu  118,  B  (     tttenden. 

12 


2  HYDROCYANIC-ACID  GAS  AGAINST   HOUSEHOLD   INSECTS. 

Perfectly  successful  experiments  were  made  during  the  summer  of 
1901  by  Mr.  W.  R.  Bent  tie,  of  the  Department  of  Agriculture,  and  by 
Mr.  A.  H.  Kirkland,  at  Boston,  Mass.  Mr.  Beattie's  experiments 
were  against  cockroaches  and  Mr.  Kirkland's  in  one  case  against 
fleas  and  in  other  against  clothes  moths. 

During  the  period  between  1901  and  1907  hydrocyanic-acid  gas 
was  used  in  practical  work  by  several  members  of  the  Bureau  of 
Entomology,  under  the  direction  of  Mr.  Marlatt,  many  residences 
and  public  buildings,  schools,  churches,  and  stores  being  fumigated 
with  practically  uniform  success.  Indeed  the  efficiency  shown  by 
this  gas  in  the  control  of  household  insects  lias  led  to  its  adoption  as 
a  standard  remedy  for  these  pests,  and  it  has  since  been  adopted  for 
the  destruction  of  insects  affecting  stored  products,  especially  for  the 
control  of  the  Mediterranean  flour  moth  (Ephestio  JcuehnieUa  Zell.) 
in  mills  and  warehouses.  For  this  purpose  it  has  proven  extremely 
effective,  having  been  used  under  the  direction  of  agents  of  this 
bureau  for  the  destruction  of  the  flour  moth  in  over  100  mills  with 
excellent  results. 

Some  entomologists  recommend  as  a  substitute  for  hydrocyanic- 
acid  gas  a  substance  which  has  been  more  or  less  effectively  used,  viz, 
carbon  bisulphid.  The  great  danger  in  the  use  of  this  latter  sub- 
stance, however,  from  its  extreme  inflammability  and  the  explosive- 
ness  of  its  vapor  when  confined,  renders  it  perhaps  less  available  and 
more  than  counteracts  the  danger  to  human  beings  from  the  use  of 
the  hydrocyanic-acid  gas.  It  has,  moreover,  been  found  that  the 
hydrocyanic-acid  gas  is  much  more  effective  for  the  control  of  all 
groups  of  household  insects,  with  the  exception  of  the  beetles,  than 
is  the  other  fumigant. 

Entomologists  have  long  noticed  that  insects  vary  greatly  in  their 
susceptibility  to  cyanic!  fumes.  The  ordinary  killing  bottle  used  in 
making  collections  contains  cyanid  of  potassium  covered  with  plaster 
of  Paris,  which  the  fumes  of  the  cyanid  penetrate.  Certain  weevils, 
and  especially  such  weevils  as  Lixus  and  Sphenophorus  and  other 
hard-bodied  forms,  will  frequently  be  left  overnight  in  a  cyanid 
bottle  and  recover  after  being  removed.  It  has  been  noticed  also  that 
in  greenhouses  certain  insects  recover.  The  experience  gained, 
however,  indicates  that  the  use  of  hydrocyanic-acid  gas  in  houses  is 
successful  against  cockroaches,  bedbugs,  fleas,  clothes  moths,  ants. 
white  ants,  house  flies,  and  other  soft-bodied  insects;  and  as  these 
constitute  the  majority  of  the  household  pests,  the  use  of  the  gas 
must  now  be  considered  a  standard  remedy.  Moreover,  rats  and  mice 
are  also'  killed  by  its  use,  and  it  fortunately  has  the  effect  of  first 
causing  these  animals  to  rush  out  from  their  holes  into  the  open,  so 
that  the  subsequent  annoyance  of  dead  mice  in  walls  and  under  floor- 
ings is  not  experienced. 


HYDROCYANN     VCID  GAS  AGAINST   HOUSEHOLD  I J  A 

DIBI  I   riONfl    I  OH    l  -i  . 

Much  experience  indicates  thai  in  order  to  destroy  the  household 
insects  mentioned,  l  fluid  ounce  of  commercial  sulphuric  acid  (ab<  ul 
1.84  sp.  gr.,  66  Bauml)  diluted  with  •">  fluid  ounces  of  water,  i<> 
increase  the  hulk  of  the  liquid  and  insure  complete  chemical  action, 
and  1  ounce  of  high  grade  (98  percent)  cyanid  of  potassium,  must 
!>«■  u-«-«l  for  everj  100  cubic  feel  of  space.  The  formula  per  hundred 
cubic  feet,  therefore,  is  as  follows: 

Potassium  cyanid  (08  percent)  avoirdupois  ounce       i 

('.■iiniirrri.il  sulphuric  acid fluid  ounce      i 

Water      fluid  ounces      3 

For  loosely  constructed  frame  houses  the  above  amounts  may  be 
doubled  per  hundfed  cubic  feet.  The  cyanid  costs  about  !<■  cents  a 
pound  and  the  sulphuric  acid  (thick  or  more  sirupy  commercial 
brand)  about  1  cents  a  pound. 

The  purity  of  the  cyanid  <  if  potash  and  sulphuric  acid  to  the  degree 
indicated  is  essentia]  i"  the  success  of  the  fumigation.  Potassium 
cyanid  may  be  obtained  in  various  "  technical  "  grades,  ranging  be- 
tween I"  per  cent  and  98  to  100  per  ceml  actual  cyanid,  the  remainder 
being  an  ineii  salt,  usually  -odium  carbonate  or  -odium  chlorid,  which 
is  of  no  value  in  fumigation  and  in  the  case  i  f  -odium  chlorid  is  a 
positive  detriment,  as  this  substance,  acted  upon  by  sulphuric  acid, 
produces  hydrochloric  acid,  which  decomposes  the  hydrocyanic-acid 
gas.  In  cases  of  extreme  adulteration  as  much  as  60  per  cent  of  the 
fumigant  may  be  decomposed  in  this  manner,  resulting  in  inferior 
effectiveness  and  tending  to  tarnish  polished  metal  surfaces  exposed 
to  the  gas.    I  f  chemically  pure  cyanid  is  used  little  tarnishing  results. 

Many  of  the  manufacturers  of  cyanid  place  on  the  market  a  "  -•>- 
called  potassium  cyanid"  which  consists  of  sodium  cyanid  adul- 
terated with  sodium  chlorid.  The  chemically  pure  sodium  cyanid 
liberates  33  per  cent  more  hydrocyanic-acid  n-.t-  than  does  the  pure 
potassium  cyanid,  so  thai  to  avoid  adulterated  chemical-  it  i-  well 
to  secure  the  -"-called  "  133  per  cent  sodium  cyanid  "  for  best  results. 
In  the  use  of  this  chemical  a  correspondingly  greater  amount  of  the 
acid  ia  necessary  for  the  complete  exhaustion  <  f  the  cyanid.1 

Before  performing  the  operation  the  house  must  be  vacated.  It  is 
not  necessary  to  remove  any  of  the  furniture  or  household  belongings 
unless  of  polished  nickel  i  r  brass,  which  may  tarnish  a  little.  Liquid 
or  moist  food-,  as  milk,  meat-,  or  other  larder  supplies  that  are  not 
dry  and  illicit  absorb  the  i_ra-.  should  be  removed  from  the  house.  All 
lire-  should  he  put  out:  for  while  the  gas  will  not  burn  under  ordi- 
nary condition-;,  it  i.-  a-  well  to  take  no  risks. 

an  Cyaald  for  Fumigation  Purposes,"  i>\  i:  s  Wogltun  (BnL 
80,  rt.  II.  Bureau  ..f  Entomology,  1»11).  Mr  Woginm'i  studies  ol  sodium  cyanid  bare 
reference  eapedali]   t"  it-  ose  in  the  fumigation  <>f  citrus  orchards 


4  HYDROCYANIC-ACID  GAS  AGAINST  HOUSEHOLD  INSECTS. 

The  cubic  contents  of  each  room  on  each  floor  should  be  carefully 
computed  and  a  tabular  statement,  .such  as  that  gives  below,  pre- 
pared, designating  for  each  floor  and  the  different  rooms  the  capacity 
and  the  amount  of  water,  acid,  and  cyanid  needed. 

Table  designating  rooms,  capacity,  and  amounts  <>i  chemicals. 


Floor. 

Room. 

Cubic  feet. 

Water. 

Vid. 

Cyanid . 

Fourth 

Garret 

i  7, 000 

2,800 
1,400 

2,200 

'  5, 500 
2.20(1 
2,000 

14,400 

2,400 
2,900 

1.21)0 
2,000 
1,800 

Fl.  <>:. 

210 

M 
42 
66 

165 
66, 

Ml 

132 
72 
87 

36 
60 

.VI 

Fl.oz. 

70 

2S 
14 
22 

55 

22 

20 

44 
24 

29 

12 

20 

is 

A  vd.  oz. 
70 

Third.. 

Front 

28 

Mid. lie 

Back 

14 
22 

Front 

55 

Mi. 1. lie 

22 

Back 

20 

First 

44 

Middle  . 

24 

29 

12 

Hall 

20 

Kitchen 

18 

Total            

37,800 

1,134 

378 

378 

1  The  charges  for  thes?  rooms  should  be  halved  and  Bet  off  in  I  wo  vessels. 

The  house  is  prepared  for  treatment  by  seeing  that  all  the  win- 
dows are  closed  and  calked,  if  of  loose  construction,  with  wet  paper 
or  cotton  batting  tucked  tightly  into  the  crevices.  Gummed  paper 
strips  are  obtainable  for  this  purpose,  which  may  be  pasted  over  the 
crevices  in  the  doors  and  windows,  making  the  room  practically 
gas-tight.  As  the  building  must  be  aired  by  opening  the  windows 
from  the  outside,  those  selected  to  be  opened  should  be  examined  to 
see  that  they  pull  down  easily,  and  if  too  high  to  be  reached  from  the 
ground  should  be  provided  with  strong  cords  reaching  to  the  ground 
that  they  may  be  easily  opened  from  below.  They  should  be  opened 
before  closing  for  the  last  time,  in  order  to  test  the  strength  of  the 
cord  and  should  not  be  pasted  up  or  calked.  The  fireplace  flues  in 
the  different  rooms  should  be  stuffed  with  paper  and  the  register- 
closed.  Carpets  and  rugs,  where  possible,  should  be  cleared  away 
from  the  floor  to  prevent  their  being  burned  should  the  acid  spatter 
or  boil  over. 

For  generators,  stoneware  or  crockery  jars  Inning  a  capacity  of  4 
gallons  are  preferable  and  may  be  used  with  a  charge  of  up  to  3 
pounds  of  cyanid.  One  of  these  vessels  should  be  placed  in  each 
room,  with  the  exception  of  large  rooms  requiring  a  charge  of  more 
than  3  pounds  of  cyanid,  when  the  charge  may  be  divided.  One 
vessel  will  suffice  for  each  3,000  or  4.000  cubic  feet,  preferably  the 
former  amount.  Under  each  of  these  vessels  a  rather  thick  carpeting 
of  old  newspapers  should  be  placed,  or  a  larger  vessel,  and  care  must 
be  exercised  to  see  that  none  of  the  vessels  is  cracked,  <>n  account  of 


HYDR0C1  \N  l«     ICTD  OAB   4QAINS1     HOI  SI  HOLD   [NSEl  0 

the  danger  of  breakage  from  the  heal  generated  bj  the  pro 
1)(H'|)  vessels  are  more  satisfacti  ry  for  the  experiment  than  the  wash 
basins  often  used,  1  >ut  the  latter  are  always  available  and  will  serve 
the  purpose.  Deeper  vessels  i_ri\c  greater  depth  to  the  water  and 
acid  and  accelerate  the  chemical  action,  and  there  is  less  danger  of 
Bpattering.  Whenever  the  room  is  of  such  size  thai  much  more  than 
.*{  pounds  of  cyanid  musl  l>c  employed  for  it,  it  is  perhaps  better  t<> 
make  two  charges  of  half  size  for  such  room. 

n:o<  ESS  01     ii    M  n.  \  HON. 

In  the  process  of  generating  the  gas  the  water  may  I"'  measured 
in  a  glass  beaker  indicating  ounces,  i  r  for  'onvenience  in  a  pinl  cup, 
and  poured  into  the  generators.  The  acid,  measured  in  the  same 
receptacle,  is  then  slowly  and  gently  poured  into  the  water  lo  av<  id 
splashing  or  boiling.  For  all  ordinary  purposes  1  pint  of  the  arid 
and  :'>  pints  of  water  arc  sufficient  f<  r  each  pound  of  cyanid.  T/u 
acid  should  never  bt   placed  in  tin   gen  \  as  advised  by 

some  writers,  since  experience  shows  thai  this  is  dangerous,  spatter- 
ing being  almosl  certain  to  follow.  When  the  arid  is  poured  into 
the  water  in  the  jar  an  ebullition  of  vapor  sometimes  arises.  Con- 
siderable heat  is  also  developed  by  the  addition  of  the  acid. 

When  the  cyanid  of  potash  is  finally  dropped  into  the  combined 
acid  and  water  mixture  an  ebullition  or  bubbling  also  take-  place 
similar  to  that  which  is  produced  by  a  red  lot  iron  dipped  into  cold 
water.  Ne\t  is  given  off  the  hydrocyanic-acid  gas,  the  mosi  poi- 
Bonous  gas  in  common  use.  It  is  colorless  and  has  an  odor  which  has 
been  likened  to  thai  of  peach  kernel-.  II'  the  fumes  are  inhaled  they 
arc  almosl  certain  to  prove  fatal;  hence  the  necessity  of  extreme  care 
and  the  advisability  of  two  intelligent  operators  in  this  work.  It  i> 
even  advisable,  especially  when  the  firsl  fumigation  is  undertaken, 
that  one  who  has  had  experience  with  this  method  of  fumigation  be 
-it  to  give  direction-.  The  odor  i-  decidedly  metallic,  like  thai 
produced  by  striking  two  pieces  of  metal  together,  or  of  metal  against 
-tone. 

The  measuring  and  preparation  of  the  water  and  acid  in  the  fumi- 
gating jars  should  be  undertaken  in  a  room  with  a  tile  or  concrete 
tloor  if  possible,  as  the  -none;  acid  used  is  apt  to  injure  wooden  floors 
Or  carpets  should  .-pillniij:  occur.  The  jar-  may  then  be  distributed 
to  the  different   rooms  and  a  bag  containing  the  requisite  cyanid 

placed  by  the  side  of  each. 

The  house  is  now  in  readiness  to  be  fumigated.  Coat-  and  hats  and 
everything  needed  outside  musl  be  removed,  and  preferably  two  per- 
sons should  then  go  to  the  top  of  the  house,  taking  different  room-  on 
the  same  floor  to  expedite  the  process,  and  place  the  hair-  containing 
the  cyanid  erentlv  into  the  vessels  to  receive  them.     The  chemical 


6  HYDROCYANIC-ACID  &AS  AGAINST  nOUSEHOLD  INSECTS. 

action  will  begin  at  once,  but  the  gas  will  not  rise  to  any  extent  for  a 
few  seconds  or  a  quarter  of  a  minute,  and  there  is  ample  time  to  leave 
the  room  quickly  without  danger  of  breathing  the  gas.  Having 
finished  the  garret  or  top  floor,  the  operators  should  pass  rapidly  to 
the  next,  and  so  on  to  the  basement,  making  their  exit  through  the 
lower  door  to  the  street. 

Hydrocyanic-acid  gas  is  lighter  than  air,  and  consequently  rises; 
therefore  the  operation  must  be  begun  at  the  top  of  the  house. 

The  house  should  be  locked  from  the  outside  and,  if  necessary,  a 
warning  sign  put  up  to  caution  against  entrance. 

The  preparation  of  the  different  rooms,  getting  their  cubic  contents, 
fixing  the  vessels,  and  preparing  the  charges,  in  a  house  of  the  size 
indicated  in  the  table  given  above,  will  take  from  two  to  three  hours, 
and  this  much  time  must  be  allowed  for.  The  house  should  remain 
closed,  for  the  gas  to  become  fully  generated  and  do  its  work,  for  4 
to  (')  hours — preferably,  however,  and  to  get  the  greatest  efficiency,  24 
hours  at  least. 

Better  results  are  claimed  for  a  warm  temperature,  say  70°  F.  or 
above,  than  in  a  temperature  as  low  as  .">0°  F.  or  below.  Under  50° 
most  insects  become  torpid  and  the  effective  action  of  the  chemical 
will  be  diminished,  especially  in  very  low  temperatures. 

At  the  close  of  the  operation  the  doors  may  be  opened  and  the 
windows  lowered  or  opened  from  the  outside,  and  after  an  hour's 
airing  the  house  may  be  entered  if  no  strong  odor  of  gas  is  detected, 
and  opened  up  even  more  thoroughly,  if  possible,  to  allow  a  complete 
airing  for  several  hours.  The  house  should  not  be  reinhabited  until 
all  traces  of  the  odor  of  the  gas  have  disappeared.  This  odor,  as 
stated  before,  has  been  compared  to  that  of  peach  kernels. 

The  contents  of  the  generating  jars  should  be  poured  into  the 
sewer  trap  or  disposed  of  in  some  place  where  they  will  not  be  a 
source  of  danger,  and  the  jars  thoroughly  cleaned. 

THE  CYAN  II)  AM)  OAS  A   DEADLY  POISON. 

In  the  use  of  hydrocyanic-acid  gas  for  household  fumigation  it 
must  not  be  lost  sight  of  for  a  single  instant  that  one  is  dealing  with 
one  of  the  most  poisonous  substances  known,  and  that  the  accidental 
eating  of  a  small  portion  of  cyanid  will  necessarily  be  fatal,  and  that 
the  inhalation  of  a  few  breaths  of  the  gas  will  asphyxiate,  and,  if 
rescue  be  not  prompt,  also  have  a  fatal  termination.  Tt  is  much 
better,  therefore,  if  fumigation  be  contemplated,  to  put  the  work  in 
the  hands  of  some  one  who  has  had  experience,  if  such  a  person  be 
available;  if  not.  to  consider  carefully  all  the  recommendations  and 
precautions  in  this  circular  and  become  thoroughly  familiarized  with 
them  before  undertaking  the  experiment. 


BYDR0C1  LHIC-ACID  0A8  AOAIN81    HOUSEHOLD  INSECTS.  7 

While  the  writer  thus  strongly  emphasizes  the  dang  ind  even 

htal  qualities  of  this  gas  when  breathed  bj  human  beings,  it  is 
worthy  of  remark  thai  in  the  thousands  of  operations  which  have 
been  carried  on  with  this  gas  in  the  course  of  its  various  applicatioi 
i„  different  parts  of  the  world,  onlj  two  ca  es  of  fatal  accidents  to 
human  beings  have  been  recorded.  These  were  due  to  extreme  car. 
lessness  in  its  use.  In  i  ne  case  the  operator  wenl  back  into  the  hou  • 
after  having  dr<  pped  the  bags  and  closed  the  building  for  some  time. 
The  abundant  experience  which  has  been  gained  by  the  differed 
members  of  the  f<  rce  of  this  office  and  manj  others  in  the  fumigation 
of  dwelling  houses  has  demonstrated  thai  all  dang  i  dy  over- 

come by  care  in  conducting  the  operation,  and  in  all  the  house-fumi- 
gation work  which  has  been  done  during  the  last  five  years  no  accid. 

has  occurred,  excepl   in  on ■  two  instances  the  burning  ol   rugs 

i„  attempting  to  set  off  charges  in  too  small  vessels  and  a  case  oi 
headache  where  a  few  whiffs  of  much  diluted  gas  had  been  acci- 
dentally breathed. 

I,  follows,  from  what  we  have  jusl  said,  that  there  may  be  danger 
from  fumigating  one  hoUse  in  a  ro*  of  houses  separated  only  by 
party  walls,  the  other  house  being  inhabited.  Unnoticed  cracks  in  a 
wall  would  admit  the  poisono  neighboring  house.     In 

Such  ;.  case  a  householder  musl  consult  his  neighbors.  In  isolated 
houses,  however,  with  the  precautions  indicated,  the  operation  will  be 

lfe  one     The  fad  that  birds  resting  on  the  ridge  of  fumigati 
houses  have  been  killed  by  the  ascending  fumes  indicates  also  that 
where  the  house  to  be  operated  upon  immediately  adjoins  a  higher 
Structure  to  which  the  gas  may  possibly  gain  entrance  there  may  be 
some  danger  to  the  occupants  of  the  higher  structure. 

It  is  undesirable  to  fumigate  single  apartments  or  rooms  in  build- 
ings and  this  should  only  be  attempted  when  the  whole  building  can 
be  vacated  during  the  operation.  In  case  of  contiguous  houses  ol 
loose  construction  an  arrangement  should  be  made  so  thai  the  adjoin- 
ing houses  also  may  be  <  acated  during  fumigation. 

In  handling  the  acid  greal  care  should  be  used  in  pouring  it  I 
the  bottle  and  in  putting  il  into  the  vessels  to  avoid  spattering  on 
the  hands  or  face,  since  il  will  burn  rapidly  through  the  skin,  and 
should  it  spatter  into  the  eyes  would  cause  serious  inflammation,  or 
it-  on  the  clothing  it  would  burn  a  hole  in  the  garment  -  Id  a 
drop  fly  to  the  hands  or  face,  bathe  the  pari  promptly  and  freely  in 
water  and  the  same  also  for  garments  or  the  carpet.  It  is  further 
dosin.blc  to  have  at  hand  a  bottle  of  annno.ua  water  to  neutralize 
the  acid  should  it  spatter  on  clothing. 

The  handling  of  the  dry  cyanid  is  not  accompanied  by  any  dai 
if  there  be  no  open  wound  on  the  hand,  bul  it  is  advisable  to  wear 
an  old  pan-  of  gloves  in  breaking  up  the  cyanid  and  putting  it  in 


8  HYDROCYANIC-ACID  GAS  AGAINST  HOUSEHOLD  INSECTS. 

the  sacks,  these  gloves  to  be  afterwards  burned.  The  fact  that  the 
cyanid  has  a  superfica]  resemblance  to  sugar  adds  to  the  danger  of 
keeping  it  about  the  premises,  and  it  is  much  better  to  at  once  deeply 
bury  or  throw  down  the  sewer  trap  any  left-over  cyanid. 

SUMMARY   OF    METHOD. 

The  general  directions  for  treatment   may  be  briefly  summarized 

as  follows : 

(1)  Prepare  tabular  statement  designating  room  capacity  and 
amount  of  chemicals  for  each  compartment,  and  secure  the  chemicals 
and  vessels  for  generating  the  gas. 

(2)  Arrange  for  the  opening  of  doors  and  windows  from  the  out- 
side at  the  conclusion  of  the  fumigation,  and  close  all  register-,  fire- 
places,  and  other  openings.  Do  necessary  calking  and  remove  carpets 
and  rugs  and  moist  food  material  and  any  metallic  objects  which  are 
likely  to  be  tarnished. 

(3)  Place  the  generating  vessels  in  each  room  with  a  thick  carpet- 
ing of  old  newspapers  under  each. 

(4)  Break  up  the  cyanid  out  of  doors  and  place  it  in  thin  paper 
sacks  containing  a  pound  or  a  half  pound  each,  suited  to  the  amounts 
to  be  used  in  the  different  rooms. 

(5)  Measure  into  each  of  the  generating  jars  the  proper  amount  of 
water,  and  afterwards  add  the  acid  slowly  in  the  proper  amount  to 
each   of  the  jars. 

(6)  Take  the  cyanid  in  baa-  in  a  basket  and  place  the  bags  to  the 
proper  amount  alongside  of  the  generating  jars  in  each  room. 

(7)  Start  at  the  top  of  the  house  and  place  the  cyanid  gently,  so 
a-  not  to  spatter,  into  each  jar.  and  quickly  leave  the  room.  Ajs 
soon  as  the  upper  floor  is  finished  go  to  the  next  lower,  and  pass  in 
tli is  manner  from  floor  to  floor  until  the  basement  is  reached  and 
exit  is  made  through  the  lower  door.  If  two  persons  work  together 
in  this  operation  they  should  both  be  on  the  same  floor  together, 
taking  different  rooms. 

(8)  The  following  day.  or  after  the  completion  of  the  fumigation, 
open  the  windows  and  doors  from  the  outside,  and  let  the  house 
ventilate  for  an  hour  before  entering  it. 

(9)  After  the  house  is  thoroughly  ventilated  and  the  odor  of  the 
gas  has  disappeared,  the  jars  should  be  emptied  in  a  safe  place,  pref- 
erably through  the  sewer  trap,  and  thoroughly  and  repeatedly  washed 
before  being  used  for  any  household  purpose. 

Approved  : 

James  Wilson, 

Secretary  of  Agricultun . 

Washington,  D.  C,  Octdbt  r  ..'/.  191 1. 

o 


UNIVERSITY  OF  FLORIDA 


3  1262  09216  5231 


